1. Field of the Invention
The present invention relates to a rubber blade for an automotive wiper, and more particularly, to a rubber blade for an automotive wiper that is changed in structure and shape so that it autonomously presses securely against an automotive windshield.
2. Description of the Related Art
An automotive wiper is a device for wiping a vehicular windshield clear of rain and other foreign substances. A wiper motor installed inside the vehicle drives a mechanical linkage to move wiper arms back and forth in a predetermined arc. Disposed on the end of the wiper arm is a detachably mounted wiper frame to which a wiper blade made of rubber is attached.
Conventional wipers attached to wiper arms include a skeletal frame and a blade portion mounted on the frame and contacting a windshield to wipe it, as shown in FIGS. 1 through 3.
A conventional wiper 10 includes: a main frame 12 having an adapter 11 thereon for mounting the wiper 10; a first frame 16 symmetrically mounted on rivet joints 13 at either end of the main frame 12, and having a blade bracket 15 for evenly distributing load on the blade 14 and holding the blade 14 inserted therein; a second frame 17 symmetrically mounted on rivet joints 13 at either end of the first frame 16, and having blade brackets 15 on either end thereof for evenly distributing load on the blade 14 and holding the blade 14 inserted therein; a blade 14 having a mounting slot 19 formed thereon along which resilient tension springs 18 and 18a having a predetermined elasticity are inserted, the resilient tension springs applying a predetermined load furnished by the first and second frames 16 and 17 along the length of the blade 14 so that the blade 14 presses evenly against a windshield when wiping it; and a metallic tension spring 18 and 18a inserted along the length on either side of the blade 14 to support the load furnished by the first and second frames 16 and 17.
Here, in order for the main frame 12 to transmit the movement of the wiper arm 10 to an arcuate movement of the blade 14, the wiper 10, blade 14, and the tension springs 18 and 18a that provide resilience to the blade 14 converge at one point so that they move in unison according to the movement of the wiper 10. Also, the first and second frames 16 and 17 evenly distribute load furnished by the main frame 12, and, along with the main frame 12, are press-formed to have holes formed therein to facilitate water drainage and reduce weight.
The blade 14 has a groove 20 running lengthwise therealong for guiding the blade brackets 15 of the first and second frames 16 and 17, and a separate mounting slot 19 for accommodating the tension springs 18 and 18a that provide resilience to the blade 14.
In the structure of this type of wiper, because the main frame 12 and the first and second frames 16 and 17 are formed separately from sheet metal and assembled together with the blade 14 and the tension springs 18 and 18a, in snowy and icy conditions of winter, the connecting and coupling portions of the unit can be hampered by frozen precipitation and thus not function properly. Accordingly, blade tension or other properties of the wiper can be affected so that the wiper is unable to aptly fulfill its wiping role.
Also, because the load on the blade is applied at certain points on the blade, it is unevenly distributed along the length of the blade. This unevenness causes premature wear of blade areas that are more compressed, while less compressed areas are prone to streak or overshoot the windshield glass underneath.
From a manufacturing point of view, the various components that are combined to form the wiper require multiple molds, which makes quality control that much more difficult, and increases the number of assembly processes that ultimately leads to a higher retail price.
The wiper shown in FIGS. 4 and 5 does not have a main frame supporting a metal frame separately from a blade, but has tension springs 18 and 18a inserted in the blade 14, over which a rubber cover 21 covers the unit.
That is, the mounting slot 19 is formed along the lengths on either side of the blade 14, tension springs 18 and 18a are inserted into each mounting slot, and a rubber cover 21 that functions as a spoiler is then inserted over the unit to conceal the tension springs 18 and 18a. This structure uses fewer parts than the above-mentioned conventional wiper, and thus avoids the problems caused by winter icing and other problems associated with wipers formed of multiple components.
However, a problem with the foresaid wiper is that the aggregate tension of the two tension springs 18 and 18a and the rubber cover 21 necessitate the wiper arm maintaining an increased load on the wiper for the wiper to be operationally effective, unduly stressing the mechanism. Also, this type of wiper is not interchangeable with existing wiper arms on vehicles that have a tension preset for the above-mentioned multi-point-type wiper blade. Furthermore, as shown in FIG. 5, because the wiper requires the rubber spoiler-cum-cover to complete the formation thereof, the latter item cannot be omitted.
Another conventional type of wiper, shown in FIGS. 6A and 6B, is formed with a separate spoiler 22 fitted at the top of the rubber blade that the tension springs 18 and 18a are inserted into. This type of blade prevents vibration, while maintaining a secure and even contact with a windshield.
However, because this wiper structure has an adapter 11 and frame 12 disposed in a vertical axis (H) direction of the adapter 11, the frame 12 or the tension spring by themselves cannot function as a spoiler. Therefore a separately formed spoiler is required, complicating the overall structure, and creating the possibility of vibration or judder caused by the spoiler and wind noise when pressed against a windshield.